3.16.37-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@xxxxxxx>
commit c7c999cb18da88a881e10e07f0724ad0bfaff770 upstream.
hci_vhci driver creates a hci device object dynamically upon each
HCI_VENDOR_PKT write. Although it checks the already created object
and returns an error, it's still racy and may build multiple hci_dev
objects concurrently when parallel writes are performed, as the device
tracks only a single hci_dev object.
This patch introduces a mutex to protect against the concurrent device
creations.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/bluetooth/hci_vhci.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
--- a/drivers/bluetooth/hci_vhci.c
+++ b/drivers/bluetooth/hci_vhci.c
@@ -50,6 +50,7 @@ struct vhci_data {
wait_queue_head_t read_wait;
struct sk_buff_head readq;
+ struct mutex open_mutex;
struct delayed_work open_timeout;
};
@@ -95,11 +96,14 @@ static int vhci_send_frame(struct hci_de
return 0;
}
-static int vhci_create_device(struct vhci_data *data, __u8 dev_type)
+static int __vhci_create_device(struct vhci_data *data, __u8 dev_type)
{
struct hci_dev *hdev;
struct sk_buff *skb;
+ if (data->hdev)
+ return -EBADFD;
+
skb = bt_skb_alloc(4, GFP_KERNEL);
if (!skb)
return -ENOMEM;
@@ -140,6 +144,17 @@ static int vhci_create_device(struct vhc
return 0;
}
+static int vhci_create_device(struct vhci_data *data, __u8 opcode)
+{
+ int err;
+
+ mutex_lock(&data->open_mutex);
+ err = __vhci_create_device(data, opcode);
+ mutex_unlock(&data->open_mutex);
+
+ return err;
+}
+
static inline ssize_t vhci_get_user(struct vhci_data *data,
const struct iovec *iov,
unsigned long count)
@@ -185,11 +200,6 @@ static inline ssize_t vhci_get_user(stru
case HCI_VENDOR_PKT:
cancel_delayed_work_sync(&data->open_timeout);
- if (data->hdev) {
- kfree_skb(skb);
- return -EBADFD;
- }
-
dev_type = *((__u8 *) skb->data);
skb_pull(skb, 1);
@@ -318,6 +328,7 @@ static int vhci_open(struct inode *inode
skb_queue_head_init(&data->readq);
init_waitqueue_head(&data->read_wait);
+ mutex_init(&data->open_mutex);
INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);
file->private_data = data;
--
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